Epidemiological data show a dramatic increase in opioid and heroin use, largely due to nonmedical use of opioid prescription medications. Nationwide efforts to reduce diversion of prescription opioids appeared to show a leveling of opioid overdose mortality rates but accompanied by a sharp increase in heroin overdose mortality rates from 2012 to 2013. Unfortunately, despite increased focus on stopping the spread of the opioid epidemic, the most recent data show both opioid and heroin use and overdose mortality rates are again increasing. Opioid abuse has traversed social, economic, and geographic boundaries. The current opioid and heroin crisis is like no other experienced in recent history. Most current heroin users started with physical addiction to prescription opioids. Unlike previous cohorts of heroin users, the majority of new heroin users are White, middle class, and live in nonurban areas. There is a lack of research on drug user populations in suburban communities. The broad goal of this revised R15 application is to fill the gap in our understanding of opioid and heroin use patterns in suburban communities where opioid use is epidemic. The study includes two specific aims: (Aim 1) To examine opioid and heroin use initiation, trajectories, settings, situations, and risk practices; (Aim 2) To compare opioid and heroin use patterns by race, ethnicity, and gender. Our qualitative study triangulates ethnographic field research and in-depth interviews conducted in three suburban field sites that differ by size, location, and demographics. The sample will consist of 180 opioid and/or heroin users living in suburban communities around Boston, Massachusetts (N=60), New Haven, Connecticut (N=60), and Atlanta, Georgia (N=60). We will use targeted, snowball, and theoretical sampling methods. Our novel use of qualitative methods with Bayesian analysis and data visualizations to illustrate transition patterns in opioid and heroin use among suburban populations is an innovation of this study design. Our collaborative and skilled research team is led by multiple PIs and includes experienced investigators who have worked together successfully on drug research projects. Our aims build on our previous suburban studies examining new trends in suburban drug use and are a logical extension of our earlier research. This study responds to an urgent need to know why opioid and heroin abuse continue to increase and what prevention and intervention programs are needed to address the opioid epidemic. Our findings will inform health care efforts targeted to suburban populations of opioid and heroin users. A more comprehensive understanding of suburban drug use, risk environments, and social context can also inform larger epidemiological studies on opioid transitions, route of administration practices, and other risk behaviors in diverse suburban areas where opioid and heroin use are increasing.